This invention relates generally to the field of video data processing and more particularly to methods and apparatus for real time digital video image processing of video image data suitable for use with a microprocessor or microcomputer and capable of providing multiple simultaneous special video effects.
In the prior art, various video special effects generating systems are known for use, for example, in broadcast television, computer graphics generation, etc. Video signal manipulation in various video environments is increasingly being carried out on video signals which have been converted to digital form. Available digital systems can individually produce a variety of known special effects. For example, it is often desirable to combine multiple independent sources of video by such known temporal video techniques as fades, wipes, or other key insertions. Other digital video systems are known for producing spatial video effects such as mosaic effects, blurring effects, scaling, or zooming. Still other digital systems generate windows, use color look up tables to provide a large palette of colors, or use specialized graphic circuits to provide computer graphics capabilities.
However, known systems are expensive and since they typically generate only a small set of effects, they do not permit close integration of multiple functions. These systems require multiple units to be combined to get multiple effects which is expensive and often presents incompatibility problems. Because the prior art systems even when coupled together do not permit close coupling of a variety of functions, they cannot generate many combinations of special effects and cannot generate many unique effects that require close integration of multiple functions. Thus, prior art systems cannot produce a wide variety of complex composite special effects where close integration of multiple functions is required.
Typically, prior art special video effects systems are self-contained systems which are designed to operate independently thereby making it difficult to interface them to a conventional microcomputer or to other special effects systems. In addition, video broadcast systems are uniquely designed to optimize video specifications such as sync, chroma burst, etc., while computer graphics systems optimize such computer specific characteristics as bandwidth, pixel definition, etc. Thus, no prior art system simultaneously optimizes both video and computer related features to permit computer control of such features as fading, blending, range thresholding, etc. This also creates incompatibilities when attempting to interface computer and video systems in a microcomputer environment. The ability to interface directly to a microcomputer bus allows video functions to be integrally combined with computer functions. This permits flexible control of video manipulation functions providing increased flexibility and extending computer control capabilities to complex video effects.
In addition, prior art video systems typically can operate in only one or a few specific targeted video environments such as a specific broadcast television market or a computer video graphics environment for a specific computer system. Thus, these prior art systems can only operate within a limited number of video standards (e.g., NTSC, PAL, etc.).